fix build on windows

[EduardoRFS]

This patch allows parmap to build on Windows, but not to run on Windows as there is no Unix.fork.

I have no idea if it's possible to make it fully work on Windows at all, using ZwCreateProcess is possible and I was able to make it work, but it's an NT API and that's hackish as it can get.

So with this libraries can still use parmap but just add an if Sys.win32 to not use parmap when it's Windows

[rdicosmo]

Thanks @EduardoRFS for this suggestion: I'm merging it!
Parmap relies on the fork POSIX primitive to do its work, and it is hard to get this working in Windows. I have no way of telling if there is interest in having Parmap working natively on Windows, but if you already know how the needed magic to support it, it would be fun to add it :-)

[UnixJunkie]

Since parmap should likely be rewritten for multicore-ocaml, then it should provide windows support easily.

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On Wed, Dec 29, 2021 at 12:46 AM Roberto Di Cosmo ***@***.***> wrote: Merged #101 <#101> into master. — Reply to this email directly, view it on GitHub <#101 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFUFAD3AK2PY555AI37QWTUTHLWHANCNFSM43TQ7YRA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[rdicosmo]

@UnixJunkie: just to avoid confusion, developing a fully compatible equivalent of parmap without Unix.fork is a highly nontrivial task, and there is no such plan at the moment.

[EduardoRFS]

I think using ZwCreateProcess is a bad idea in general, so for windows it should probably just use the main process. So that at least the compatibility is there.